Some guides instruct the user to create a directory at /etc/puppet/manifests and to place .pp files in that directory. However, doing so results in a non-working puppet install since, by default, puppet has defined defaults.

The correct way is to determine the defaults and work with them. With Puppet installed, issue for instance:

puppet config print | grep manifest

and, at least on Debian, the output will be along the lines of:

default_manifest = ./manifests
disable_per_environment_manifest = false
genmanifest = false
manifest = /etc/puppet/code/environments/production/manifests
ordering = manifest

which means that .pp files should be placed in /etc/puppet/code/environments/production/manifests.

It is possible to edit /etc/puppet/puppet.conf and change the defaults, however doing so comes at the cost of maintainability as well as possible incompatibility with the distribution defaults.

• install Puppet using the distribution package manager
• to set up a master:
  • edit /etc/puppet/puppet.conf and:
    • add server = myserver.tld to the [main] section (where myserver.tld represents the hostname of the current machine; of the master),
    • add dns_alt_names = myserver.tld to the [master] section (where myserver.tld represents the hostname of the current machine; of the master),
  • issue puppet config print | grep "^manifest =" in order to determine where the .pp files should go,
    • add files to the directory, for instance site.pp
  • issue puppet apply -t --verbose site.pp inside the manifest directory
• to set up an agent:
  • edit /etc/puppet/puppet.conf and:
    • add server = myserver.tld to the [main] section (where, myserver.tld represents the hostname of the Puppet master),
  • issue puppet agent -t --verbose from anywhere to start provisioning the agent,
  • issue puppet cert list on the master to show all pending certificates waiting to be signed,
  • issue puppet cert sign AGENT on the master where AGENT is the configured agent,
  • issue puppet agent -t --verbose from anywhere once again to start provisioning the agent.

As an example, assuming that a server is a dedicated seedbox machine, one would like to switch the TCP congestion protocol to lb over htcp or others. The following ERB template branches on the server FQDN and sets the TCP congestion protocol:

<% if @fqdn == "media.home" %>
net.ipv4.tcp_congestion_control=lp
<% else %>
net.ipv4.tcp_congestion_control=htcp
<% end %>